Auxiliary Air Valve System

NOTE: Install tachometer when checking auxiliary air valve system. Ensure tachometer is connected to proper terminals. For tachometer connections, see IDLE SPEED & MIXTURE in ADJUSTMENTS - 4-CYL or ADJUSTMENTS - V6 articles.

CAUTION: Some tachometers may not be compatible with ignition system. Consult tachometer manufacturer before connecting tachometer to system. To avoid possible damage to ignitor and/or coil, DO NOT allow tachometer terminal to become grounded.

Install tachometer. With engine coolant temperature less than 176°F (80°C), start engine.
With engine idling, turn idle speed adjusting screw inward to bottom of bore while counting number of revolutions. See Fig 1 and Fig 2 . Engine speed should decrease noticeably.
Return idle speed adjusting screw to original position. Warm engine to normal operating temperature. Repeat step 2. Engine speed should not change or should drop slightly.
If engine RPM does not respond as indicated, check for vacuum leaks or restricted auxiliary air valve circuit. If no defects are found, replace auxiliary air valve, located on bottom of valve body.

Fig 1: Idle Speed Adjusting Screw ID (2.4L)

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Fig 2: Idle Speed Adjusting Screw ID (3.0L)

Testing information not available from manufacturer.